It is known to produce printed products by assembling folded sheets or folded partial products, wherein at successive feeding points these are placed on to saddle-shaped supports being conveyed continuously and usually aligned transverse to the conveying direction, such, that the inner fold line of the first folded sheet or partial product is lying on the saddle line of the support and the two folded parts are supported by the support or hang substantially freely downwards, and such, that further supplied sheets or partial products are placed on to the first sheet and on top of one another. For folding sheets or partial products in the named manner, for example, a rotating collecting drum is utilised, in which a plurality of saddle-shaped supports are arranged in star-form. The saddle lines of the saddle-shaped supports extend in axial direction on the circumference of the drum. The axial length of the saddle-shaped supports and of the saddle lines usually is longer by a multiple than the length of the fold lines of the printed products to be produced and these are displaced on the supports in such a manner, that every printed product under production is moved around the axis of the drum several times in a spiral-shaped track and in each one of these rotations, usually in the area of the upper zenith of the drum, passes a feeding point, where another sheet or partial product is placed on to the sheets or partial products already lying on the saddle-shaped support.
Also known are linear assembling installations, in which the saddle-shaped supports, which again are arranged essentially transverse to the conveying direction, are conveyed in a more or less straight line past feeding points arranged one after the other in such a manner, that the products being produced do not have to be displaced along the saddle lines.
It is also known to process printed products produced by assembling during their further conveyance on the saddle-shaped supports (in the collecting drum or in a linear system). For such processing they are treated in the area of their fold line lying on the saddle line, namely between a tool and a counter-tool, wherein the tools act on the fold area of the printed product, the tool from outside and the counter-tool from inside, i.e. from the side of the saddle-shaped support. It is in particular known to staple folded printed products during their conveyance between a stapling head (tool) and a folder (counter-tool) or to clamp the printed products for measuring their thickness between an external probe (tool) and an internal probe (counter-tool).
When, for the mentioned type of processing, the conveying speed of the saddle-shaped supports is relatively high and the processing is to be carried out reliably and without any impairment of the printed products, it is according to the current opinion necessary, that the distal ends of tool and counter-tool, between which the processing is carried out, are arranged at the same level as the saddle line and that tool, counter-tool, and saddle-shaped support are conveyed such that their positions relative to each other remain unchanged for at least a short time. Only in this manner there are no relative movements between tool and counter-tool and between tools and saddle-shaped support during the processing, which relative movements may undesirably deform or damage the products lying on the saddle-shaped supports. In accordance with prior art, this is achieved with various measures.
For example, every saddle-shaped support is equipped with a tool and a counter-tool and conveyed together with these, wherein, when conveyed through a predefined part of the conveying track, the tool and/or the counter-tool are brought into a processing position relative to one another (distal tool ends in the area of the saddle line of the saddle-shaped support) and are activated. For the processing, i.e. during conveyance through a processing zone, tool and counter tool are held in the named processing position. By equipping the saddle-shaped supports in the named manner, it is easily possible to maintain tool, counter-tool and saddle-shaped support stationary relative to one another (in processing position) even during a lengthier processing period. On the other hand, however, it is very expensive to equip all saddle-shaped supports correspondingly, this in particular in the case of systems, in which the printed products are conveyed over relatively long stretches on saddle-shaped supports arranged tightly behind one another and are to be processed in various manners. If the tools or the saddle-shaped supports equipped with the tools respectively also have to be correspondingly adjusted for enabling processing of different printed products, production changes are associated with a lot of work and as a result of this with lengthy production losses, which may well represent a further disadvantage.
It is also known to arrange the tools in smaller numbers along shorter circuits and to a limited extent independent from the circuit of the saddle-shaped supports and to connect the counter-tools either with the saddle-shaped supports (e.g., described in EP-0546326 or EP-0606555) or with the tools (e.g., described in EP-1245406. The circuit of the tools and the circuit of the saddle-shaped supports are adapted to one another in the processing zone in such a manner, that there are undesirable relative movements neither between tools and counter-tools nor between tools and saddle-shaped supports. This means that the circuits of the tools, of the counter-tools and of the saddle-shaped supports have at least through the processing zone a constant distance from each other and the same directions, wherein tools, counter-tools and saddle-shaped supports are aligned to one another during the conveyance through the processing zone, i.e. they are conveyed in synchronism. It is particularly advantageous, because easily implemented with respect to the installation, to realize the circuit of the tools to be a round circle and to arrange as few tools as possible (if so required with counter-tools) along this circuit, i.e. keep the radius of the circular circuit as small as possible. The circuit of the saddle-shaped supports (if so required with counter-tools) is then at least in the processing zone to have the form of a circular arc having the same centre as the circuit of the tools and also a relatively small radius. This, however, leads to constraints regarding space, which may be serious and undesirable in particular for cases, in which different processing operations are to be carried out in successive processing zones.